Concept:Euphemism, oxymoron, and hyperbole are all figures of speech, while rhythm is a sound-based poetic device.
Explanation:Option A: Euphemism is a mild expression used in place of a harsh or unpleasant one, so it is a figure of speech.
Option B: Oxymoron combines two opposite or contradictory ideas, making it a figure of speech.
Option C: Hyperbole uses deliberate exaggeration for effect, which is also a figure of speech.
Option D: Rhythm refers to the pattern of stressed and unstressed syllables in poetry, not a figure of speech.
Therefore, three options belong to the same category, but rhythm does not, making it the odd item.
Answer:D. Rhythm